This invention generally relates to plate-fin type heat exchangers. More particularly, this invention relates to a heat exchanger assembly having core-reinforcing closure bars.
Plate-fin type heat exchangers with various fluid flow patterns are well known. Typical arrangements include a core that comprises stacked layers of continuous corrugated fin elements. Each layer typically is mounted so that the channels formed by the fins in one layer are oriented relative to the channels formed by the fins in an adjacent layer so that fluid flow through the channels is in different directions. A parting sheet typically is placed between adjacent fin layers to maintain separation between alternate fluid flow paths. Top and bottom cover sheets typically are included at the ends of the heat exchanger core for structural support.
Conventional arrangements include closure bars mounted on the core sides that act as seals maintaining fluid flow in the desired direction through the channels.
One innovation in the design of closure bars is shown in U.S. Pat. No. 4,301,863, where extensions on the closure bars are provided to establish a spacing between the heat exchanger core and the locations where headers are welded to the closure bars. While such an arrangement has proven effective, those skilled in the art are always striving to make improvements.
One challenge facing designers of heat exchangers includes the competing interests between structural integrity and weight. Lightweight designs are particularly desirable for aircraft applications, for example. Utilizing less material or lighter weight materials, however, can be problematic if the structural integrity of the core is not sufficient to withstand the temperature extremes experienced by the heat exchanger. It has proven difficult to establish a heat exchanger design that withstands extreme temperatures, yet operates efficiently and does not weigh too much.
This invention addresses the need for an improved design by providing a heat exchanger assembly with closure bars that reinforce the core of the heat exchanger while minimizing the amount of additional weight compared to other designs. Additionally, the inventive arrangement strikes a balance between maximizing the efficiency of the heat exchanger while providing the desired enhanced structural integrity.
In general terms, this invention is a heat exchanger having core-reinforcing closure bars.
A heat exchanger assembly designed according to this invention includes a plurality of first fluid pathway layers that allow fluid to flow in a first direction through the assembly. A plurality of second fluid pathway layers allow fluid to flow in a second direction through the assembly. A parting sheet separates each of the fluid pathway layers. A plurality of first closure bars are associated with the first fluid pathway layers. The first closure bars have a solid surface that is operative to guide fluid through the first fluid pathways in the first direction. The closure bars have a reinforcing portion extending at least partially into the first fluid pathways. The reinforcing portion of each closure bar has first and second reinforcing members on opposite sides of a modified flow passage. The first and second reinforcing members are secured to corresponding ones of the parting sheets, respectively.
A second plurality of closure bars preferably is associated with the second fluid pathway layers. The second closure bars, like the first closure bars, preferably have a solid surface operative to guide fluid through the second fluid pathways in the second direction. A reinforcing portion of each second closure bar extends at least partially into the corresponding second fluid pathway. The reinforcing portions, in one example, have first and second reinforcing members on opposite sides of a modified flow passage. The first and second reinforcing members are secured to corresponding ones of the parting sheets, respectively.
In one example, the closure bars and fluid pathways are oriented so that the two different directions of fluid flow through the exchanger assembly are perpendicular relative to each other.
In one example, the reinforcing portions modified flow passages have a generally C-shaped cross section. The reinforcing portions preferably extend in toward a center of the core in a direction perpendicular to the fluid pathways varying distances along the length of the core of the heat exchanger assembly. The reinforcing portions preferably extend further into the core near ends of the heat exchanger where deformation is more likely. Near the central portion of the heat exchanger, the reinforcing portions preferably extend less toward the center of the core. Having varying dimensions of the reinforcing portions, facilitates enhancing the structural integrity of the assembly while minimizing the amount of material weight.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiments. The drawings that accompany the detailed description can be briefly described as follows.